Mechanism for player pianos



Dec. 2, 1930. w. B. TUNSTALL 1,783,319

MECHANISM FOR PLAYER PIANOS Filed July 11. 1927 SSheets-Sheet 1 wig wasFlal INVENTOR.

Dec. 2, 1930. w. B. TUNSTALL 1,783,319

MECHANISM FOR PLAYER PIANOS Filed July 11. 1927 5 Sheets-Sheet 2 & Q%%ZZWZ Dec. 2, 1930 w. B. TUNSTALL MECHANISM FOR PLAYER PIANOS FiledJuly 11. 1927 3 Sheets-Sheet 3 fly M W ATTORNEY II I I I FIGE EWCXIatented Dec. 2, 1939 UNITED STATES WILLIAH! B. TUNSTALL, OF WORCESTER,MASSACHUSETTS MECHANISM FOR PLAYER PIANOS Application filed July 11,

My invention relates to player pianos and has particular reference to animproved construction of the pneumatic. action for striking the notes ofthe piano.

Some of the objects of my invention are to produce more simple andcompact player pianos than have been heretofore constructed, to reducethe number of parts embodied in the pneumatic action, to insureaccessibility of the parts of the pneumatic action for eitheradjustment, repair orreplacement, and to facilitate the standardizationof the parts of the pneumatic action for instruments of varying scaledimensions.

Heretofore it has been the-common practice of manufacturers of playerpianos to locatethe pneumatic action for striking the notes of the pianoabove the piano key bed and to place the bellows and other auxiliaryparts below the keys, thereby necessitating the interconnection of thevarious elements by a number of rubber tubes. By my invention, Ireorganize the entire structure of the pneumatic action and itsassociated elements, by combining in a single unit, not only the bellowsand pneumatic units but also various other auxiliary parts of thepneumatic mechanism. In my improved construction, I

eliminate a large number of parts heretofore employed by making one windchest serve as a common wind chest for the entire pneumatic mechanism,thereby eliminating the necessity for connecting the various separatedelements by rubber tubing, with a resuiting reduction in the cost ofmaintenance of the instrument.

Furthermore, my invention results in a great saving in the cost ofmanufacture of pneumatic actions for instruments of different scalerange, due to the fact that in- SJGEld of providing two or more rows ofstriking pneumatics arranged one above the other, as in common practice,my improved construction employs only one row of striking pneumatiesarranged in sideby side relation. My

improved pneumatic units are so constructed that they can be placed inapproximate vertical alignment with the corresponding notes to be struckon the piano, each pneumatic unit being a duplication of the others;thus per- 1927. Serial No. 204,873.

mitting wind chests for different pianos to be bored or grooved alike inaccordance with the scale range of the piano. In other words, a largenumber of standardized parts can be employed in constructing pneumaticactions for pianos of different scale ranges, the single row arrangementof pneumatic units being extremely flexible as regards instrumentshaving different proportions. The above and other advantageous featuresof my invention will hereinafter more clearly appear in the accompanyingdrawings in which Fig. l is a view partially in section and partially inend elevation of a portion of an upright piano provided with my improvedpneumatic action.

Fig. 2 is a front view of the parts shown in Fig. 1 on a reduced scale.

Fig. 3 is a perspective view of one of my improved pneumatic unitsremoved from the piano.

Fig. 4 is a perspective view of the unit shown in Fig. 3 with the powerpneumatic removed.

Fig. 5 is a perspective view similar to Fig. 4 looking at the other sideof the unit.

Fig. 6 is a sectional view through the unit along the line 6, 6 of Fig.5.

Fig. 7 is a sectional view along the line 7 7 of Fig. 5.

Fig. 8 is a sectional view similar to Fig. 6 showing the power pneumaticin collapsed condition to strike a note.

Fig. 9 is a fragmentary sectional view along the line 9, 9 of Fig. 2.

Like reference characters refer to like parts in the different figures.

Referring particularly to Figs. 1 and 2, the spool box 1', of any usualconstruction, has mounted therein the trackerbar 2, take up spool 3 andthe tubes 4, leading from the tracker bar 2 to my improved pneumaticaction, which is located just below the spool box. The action comprisesa main channel board 5, having a bellows section or chamber 6 and anaction section or wind chest 7 mounted on the board 5 and in directcommunication with a row of pneumatic units 8, secured to the chest 7 bymeans of the screws 9 extending through holes 9a in the units, thedetails of which units will be hereinafter described.

Rigidly secured to the board 5 in any suitable manner as by glue andscrews 5a and in communication with the bellows section 6 areinountedthe feeders or exhausters 10 and the reservoir 11. The movableleaf 10a of each feeder 10 is connected by means of the link 12 and lugl3-to any suitab e pedal mechanism," not shown bcnea "r tne key bed ofthe piano. The exhaustcrs 10 provide valves 1% and 15 toregulate. the.

flow of air from the bellows section 6 to the reserv ir 11. 1 i l Thewind chest 7 provides spaced ducts each adapted convey the effect of thev cuum in the chest 7 to a striker pneumatic 2O althoughit is evidentthat this stop 21 can either engage directly with the end of the wippenor be solplaced asto engage the striking lever 19, cai'rie-dby a strikerunit 8. As is ordinarily th practice the key 22 can operate the wippen'20 to strike the notes independently of the player mechanism, ortheplayer mechanism. can be op- "erat'ed independently of the keys '22.

Referring to'llig. 2, a number oftparts not directly related-tothepresent invention are shown as comprising the wind motor 23 foroperating-the roll mechanism; through transmission'or gear mechanism andthe automatic tracking mechanism with-' in the boX 25'. The tempogovernor and ac' tion shut off are contained within the box 26 while thehammer rail pneumatics for the treble end, and bass end are shown at 2"?and 28, respectively. The loud pedal or damper lifting pneumatic isshown at 29.

Referring now'to F 3 to 8 inclusive,

it will be seen thateach pneumatic unit 8' consists of an L shapedblocl-:, preferablyof wood and fabric, theelongated portion 8a of whichprovides a bevelled projection 30 to which the center leaf 18 of thepower V pneumatic is hinged by means of a piece thin fabric gluedto theprojection 30 and attached to the center leaf 18, and to the end of theoutside leaf 17 respectively. The center leaf 18 provides a passage 180;leading to the space between the center leaf l8 and the outer 17, thetwo leaves in combination giving I added power to the action of thepneumatic as'compared: to a single leaf pneumatic.

' v As, best shown in Fig. 3 the rubber tube 4 leading from,thetrackerbar' 2 is connected to the unit block 8- by means of a nipplewill be hereafter termed a power oneuinatic.

31 which leads to a longitudinal channel provided in the elongated blockportion 8a. This channel 32 leads into an annular opening 33 on one faceof the block 8, and this channel 32 also is in communication with a tube3% located in a hole 35 extending tranr: versely through the block.passing through the block goes through a slot 36 extending from thecenter of the block to the power pneumatic, as clearly shown in Figs. 4;and 5. Theend of the tube 3a oppositeto the channel 32 is partiallyclosed by a closure 37 providing a small vent strictedcommunication-with a recess 39 provlded 1n the face of the block 8 1nthe form of a shallow bore. The recess 391s in turn in communicationwith similar recesses 39c and 39b, and the latter recess 39b'iscommunication with a vertical slot 38 that is adapted to register with aduct .16 extend ing from the wind chest 7, as shown in Fig. 1. Thus thevent 37a is in direct communication with the windchest 7 through thechannel 38 which may be readily made The tube 34: in

hole 37a so -that the channel 32 is in re- 1 by a circular saw cuttingintothe block. un f til it'enters the recesses 39aand 39?).

In addition to the rather shallow recesses 39, 39a and39b, the face ofthe block shown in Fig; 5 is provided with adeeper recess 41-0 wlnch isIn communication wltht-he smaller. recesses 39a. and 39b; The recess lOprovides anannular shoulder 4066' around, which is adapted to seat avalve 41 so as to close :the central opening 42 of the block into whichleads the slot 36 previously referred to. The valve 41 is carried on aspindle 43 which is slidable a guide n located in the central hoole42and carries at its other endia' valve 15 engageable with a raised seat46 surrounding the shoulder between the recess 33 and the centralopening 12. Qlhe valve 45v is in turn carried by a diaphragm l? which isanchored around its periphery to a shoulder 43- in the recess 33 bymeans of a ring 49. The side of the diaphragm 4L7 oppositetothe valvel?) carries a disc 50 which bears against the side wall 51 of the blockunit when the diaphragm 471s in. the position shown in Fig. 6.

It is apparent that the disc 50' di idesthe i recess33 into two chambersand the inner chamber 33a is in communicationwith the atmosphere througha duct 52 provided in the bottom of the block, as clearly shown in Fig.3. The recesses 39 and 40am shut oil" from the; atmosphere by the sidewall 53 at tached to the block, both side walls 51- and 53 preferablybeingin the form of thin cardboard strips which canbe readily glued tothe wooden sidesof the block, although obviously metal plates could beemployed for'the' same ,PU 'PQ It. is-to be noted particularly that thevari ous ducts 36, 38; and 52 are shown as being madeby'th'e use ofsmall circular sawsof the proper diameter while the various recessessuch as 33, 39, and 40 are shown as being made by the use of boringtools. I have found that by so making the ducts and recesses in thewooden block of each unit it is possible to produce standardized blocksproperly recessed and slotted, in very large quantities, with arelatively small expenditure of time and labor and with absoluteaccuracy. It is to be understood, however, that the principle of myimproved pneumatic unitis in no way dependent upon the exact form of thevarious ducts and recesses which can be made in other ways than as shownto obtain the same results.

Referring particularly to the operation of the various working parts;when either of the movable leaves 100, of the exhausters 10 are moveddownward, the air is exhausted through the valve 15 and through thebellows chest 6 to the reservoir 11, with the result that the movableleaf 10 is drawn upward against the pressure of a spring of any standardtype. The vacuum thus created is locked against the atmospheric pressureby means of the valve 15 and is available for operating the strikerpneumatic units 8, after passing through a valve 54 in the gate box 26;as shown in Fig. 9 the said valve 54 is provided to control the flow ofair from the bellows chest 6 to the action wind chest 7. A spacer block55 extends between the end of the channel board 5 and the box 26, theblock 55 providing passages 56 and 57 communicating with the bellowssection 5 and the wind chest 7. The valve 54 is slidable by means of awire 58 to either permit the flow of air between passages 56 and 57, aswhen in operation, or to shut off the air when rerolling. The vacuum inthe action chest 7 is conveyed through the slots 16 and 38 to the vacuumchambers 39, 39a and 39b, and the special valve chamber or recess 40.The vacuum thus created is in communication with the vent tube 84,through the vent 37a.

The vacuum passing through the vent 37a being transmitted to one side ofthe diaphragm 47 by means of the tube 34; so long as the opening in thetracker bar 2 covered by the nbte sheet, the diaphragm 47 will tend tohold the valve 45 open and the valve 41 closed, due to atmosphericpressure in chamber 33a and the fact that the valve 45 and the valve 41are connected by means of the valve spindle 43 and the valve spindle isguided by means of the guide 44.

Atmospheric pressure entering the duct 52 is the active force whichtends to draw or force the diaphragm 47 away from the valve seat 46, andwhen the valve 41 is closed and the valve 45 opens, the atmosphericpressure entering the duct 52 passes through the chamber 33a to the slot36. From the slot 36, air at atmospheric pressure enters the interior ofthe power pneumatic and thus maintains the pneumatic at rest, due to thefact that atmos pheric pressure is both within and without thepneumatic.

When an opening in the tracker bar 2 is exposed, atmospheric pressureenters the cor- The vacuum in the chamber 40 then enters around thevalve 41, into the hole 42 and through the groove 36 into the interiorof the power pneumatic.

The pressure in the interior of the power pneumatic thus being reduced,atmospheric pressure forces the power pneumatic to collapse, with theresult that the note is struck by the lever 19 as the upper leaf 17moves downwardly. It is obvious that the action of the power pneumaticis quick and positive owing to the direct connection of the lever 19 tothe leaf 17 with no motion lost transmitting the action. Furthermore, itis apparent from Fig. 2 that each pneumatic striking unit 8 practicallylines up with the corresponding note, so that the levers 19 extendrearwardly from the single row of units without interference, each lever19 permitting a small amount of lateral bending to bring it directlybelow the corresponding wippen.

From the foregoing, it is apparent that I have provided an improvedpneumatic action for a player piano comprising striking units so formedthat only one row of units is necessary for the entire mechanism, eachstriker unit being a complete valve mechanism in itself.

It will be further observed that by providing all the necessary parts inone complete unit just above the key board, I have eliminated the needof any channel board in connection with the wind chest of theinstrument.

In the process of manufacturing piano player mechanisms, those schooledin the art will readily understand the great saving that has beenprovided by my improved form of structure. Whereas, it was necessary,heretofore, to honeycomb valve boards, pouch board, and channel boards,and then dip them in several baths of shellac or other insulatingmaterial to make them wind tight; by means of this invention, all thiswork is eliminated, as is also, the danger of cross leaks and troubledue to checking of the wood thus honeycombed.

Furthermore, by this process of elimination, I have been enabled tobuild an action, the mechanism of which is so small that I 70 respondingtube 4 and passing through the can-incorporate the entire bellowsmechanism and other parts into one unitary structure above the key bedof the piano thus simplifying the Work of installation and alsoproviding an action which-can be tested and regulate'd, in its entirety,before installation. I claim: v 1. In a mechanism for automatic musicalinstruments, in comhination,a plurality of 11 similar pneumatic powerunits and a single 'wind chest having two, chambers, one conne'cting theeXhausters and the reservoir, and the other torming'a common channel forconveying the vacuum effect from said exhausters to pneumatic powerunits fastened thereon.

3 2. In an automatic musical instrument, a unitary wind chest playeraction mechanism mounted thereon above the keys including 1 a commonwind chest, striker pneumatics and valve mechanism to controlcommunication between the striker pneumatics and'the wind chest,exhausting devices carried by the wind chest, in direct communicationtherewith, and

7 as means foroperating the exhausting devices.

8. An automatic musical instrument having a key bed, a wind chestdisposed above the key bed, exha'usters mounted on and indirectcommunication with the wind chest 30 and adapted to exhaust airtherefrom, and

operating means for said ez zhaustersr [4. An automatic musicalinstrument having' a key bed, a wind chest mounted there above, strikerneumatics mounted on the wind chest, exhausting devices carried by thewind chest and. in direct communication therewith, operating mechanismfor the exhausters disposed below the key bed, and connections betweensaid' exhausters and the 1') operating mechanism.

7 5. In an automatic musical instrument, an action wind chest, strikerpneumatics supported thereby, and exhausting devices also supported bythe wind chest in direct communication therewith,

6. in a mechanism for automatic musical instruments, the combinationwith a wind chest providing separate chambers extending the length ofthe instrument, a series of pneumatic power units for striking the notescarried by said wind chest and connected individually to one of saidwind chest cham- V bers, an air oXh-auster and reservoir carried by anddirectly connected to the other of said wind-chest chambers and parallelpassages extending from both of said winc chest chambers at one end or"the instrument, of a valve interposed between said passages forcontrolling the travel of air from one wind chest C9 chamber teanother,and means for moving said valve to prevent the low of air between saidpassages and thereby cut oil the power units from said eXhauster.

WILLIAM B. TUNSTALL.

